RE: The Toyota Corolla XRS has an 11.5:1 compression, do you think it can get by on 89 octane?
IF it has knock sensors it should be able to get by with it. I don't think just testing it out one time will hurt it. My aunt always puts 87 octane in her Altima 3.5L SL despite the recommendation for Premium and she hasn't had problems yet 50,000 miles later. That is my guess.
To wallstreetman, from what I have always heard the pharse Recommended means they suggest premium if you want the best results for an engine, but it has been made so then it can run on lower grades. The premium will allow the engine run on its full potiental, the knock senors will hold the engine back a bit so then the engine doesn't receive damage. On my engine it recommends 89 but is stated that it can use 87 but it warns that the engine won't run at its full potiental. When I ran 87 in it a few times I was low on $$$, the engine ran the same in terms of not knocking, but it didn't feel quite as responsive as when I ran the recommended 89 in it.
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